In Japanese Unexamined Patent Application Publication No. 2011-178917A, claim 1 describes “a rubber composition for heat-resistant conveyor belts comprising an ethylene-α-olefin copolymer having a melting point of 40° C. or lower,” claim 2 describes “further comprising an ethylene-propylene copolymer having an ethylene content of 60 to 80 mass %,” and claim 3 describes “the ethylene-α-olefin copolymer is an ethylene-1-butene copolymer having a melting point of 40° C. or lower.”
The present inventor has investigated the rubber composition for heat-resistant conveyor belts described in Japanese Unexamined Patent Application Publication No. 2011-178917A, and discovered that heat resistance is insufficient. Specifically, the tensile strength (TB) at 150° C. is small, and the rate of change (ΔTB) between the tensile strength at room temperature and the tensile strength at 150° C. is large.